When operating an agricultural machine, such as a forage or combine harvester, one can sometimes pick up from the field an article that interferes with the operation of the machine or a blockage may occur within the machine for any of a variety of reasons. In such an event, the moving components involved in harvesting and processing the crop, need to be stopped so that the obstruction can be located and the problem remedied.
The moving components are usually accessed by removing a cover and for safety reasons it is important that the cover should not be removed until all the moving components have come to a standstill. Safety legislation in many countries requires an audible alarm to be sounded while it remains dangerous to remove the cover protecting the moving components.
The components are not normally braked and, as a result, after the operator disengages the drive from the vehicle engine, the components continue to rotate for a considerable time on account of their own inertia. Waiting for the machinery to come to a complete standstill sometimes proves too frustrating for the operator and through impatience the cover is opened too soon, thereby creating a serious risk of injury to the operator.